Periostin Promotes Sarcoma Growth by Promoting Tumor-Associated Macrophage Migration and Differentiation

Area of Science:

• Oncology
• Immunology
• Biochemistry

Background:

• Soft-tissue sarcomas (STS) exhibit significant extracellular matrix (ECM) deposition.
• The precise role of specific ECM components in STS progression and immune evasion is not fully understood.

Purpose of the Study:

• To investigate the role of periostin (POSTN) in regulating sarcoma progression and the tumor immune microenvironment.
• To explore POSTN as a potential therapeutic target in STS.

Main Methods:

• Analysis of human STS datasets and murine genetic sarcoma models.
• In vivo functional silencing of Postn and in vitro mechanistic studies using recombinant POSTN.
• Single-cell RNA sequencing and therapeutic neutralization of POSTN.

Main Results:

• High POSTN expression correlates with poor prognosis and elevated ECM and myeloid cell gene expression in human STS.
• Postn silencing in murine models reduced tumor growth via non-cell-autonomous mechanisms, increasing CD4+ and CD8+ T cell infiltration and decreasing immunosuppressive myeloid cells.
• POSTN acts as a chemoattractant and differentiation cue for monocytes, promoting their maturation into tumor-associated macrophages (TAMs).

Conclusions:

• POSTN is a key stromal regulator in STS, mediating immune evasion through myeloid cell recruitment and education.
• Targeting POSTN presents a potential adjuvant strategy to enhance immunotherapy efficacy and overcome immune exclusion in sarcoma.